Is my own unpublished work used again plagiarised ?

Hello,

I am a masters student and writing my internship paper for university submission. I wrote a paper previously on the same topic, however the professor did not approve the work with the reason "objective not met". The paper went under University's plagiarism checker and was clean. Now I wish to directly copy some of the content from this previous paper(failed) into my new paper. I have heard that once a paper is checked with the plagiarism checker, it is stored in the database. Now my question is, if I use the content and if the system detects it as plagiarized from my previous paper, will it be a case of plagiarism ?

Thanks in advance.

Rishab